text: import React from 'react'
  import styles from './nav-style';
  
  const { func, bool } = React.PropTypes
  
  function getPrevStyles(props) {
      return props.hasPrevious ? styles.prev : styles.prevHidden
  }
  
  function getNextStyles(props) {
      return props.hasNext ? styles.next : styles.nextHidden
  }
  
  function Nav(props) {
    return (
      <div style={styles.root}>
        <button style={getPrevStyles(props)} onClick={props.onPrevious}>&#10094;</button>
        <button style={getNextStyles(props)} onClick={props.onNext}>&#10095;</button>
      </div>
    )
  }
  
  Nav.propTypes = {
    onPrevious: func.isRequired,
    onNext: func.isRequired,
    hasPrevious: bool,
    hasNext: bool
  }
  
  export default Nav
  